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Main => Woodworking => Topic started by: shponglefan on June 10, 2018, 05:49:15 pm

Title: Filling in shallow grooves on a plywood desk top?
Post by: shponglefan on June 10, 2018, 05:49:15 pm
I'm building a desk using two sheets of plywood. After cutting and laminating things together, I've noticed the side I intend for the top of the desk has these shallow pits/grooves at one end. They're not very deep (less than a mm) and don't really look like grooves from a distance. I thought they were part of the grain pattern which is why I didn't notice them at first.

I plan to stain and finish it with polyurethane. I'd like to fill in these grooves to achieve a smooth surface.

Would using polyurethane be enough, if I started with the grooves and built a coating? Or is there another type of filler I could use first, before finishing with polyurethane?
Title: Re: Filling in shallow grooves on a plywood desk top?
Post by: _Iz- on June 11, 2018, 01:15:55 am
You can buy wood filler that can be stained
Title: Re: Filling in shallow grooves on a plywood desk top?
Post by: shponglefan on June 11, 2018, 08:33:43 am
You can buy wood filler that can be stained

My issue with that kind of filler is that it usually looks substantially different than the natural grain, even after staining. Basically it may end up sticking out like a sore thumb.

That's why I'm hoping to preserve the existing look.
Title: Re: Filling in shallow grooves on a plywood desk top?
Post by: Malenko on June 11, 2018, 08:54:12 am
You can buy wood filler that can be stained

My issue with that kind of filler is that it usually looks substantially different than the natural grain, even after staining. Basically it may end up sticking out like a sore thumb.

That's why I'm hoping to preserve the existing look.

Try it on a scrap piece. 
Title: Re: Filling in shallow grooves on a plywood desk top?
Post by: jennifer on June 11, 2018, 12:43:03 pm
Sand the whole top with a belt sander, lightly and evenly in multiple directions, starting with 400grit, getting progressivly finer, don't just dig on the problem area.
Title: Re: Filling in shallow grooves on a plywood desk top?
Post by: Mike A on June 11, 2018, 12:45:38 pm
Jennifer is 100 percent correct. Less than 1mm? Just sand the whole top down.
Title: Re: Filling in shallow grooves on a plywood desk top?
Post by: bperkins01 on June 14, 2018, 09:48:39 am
The face ply of plywood is likely about 1mm thick..  I would not use a belt sander.. 
hand sand the surface of the entire sheet using 220G paper and a sanding block..  Sand the scratches as best you can.  Depending on the type of plywood - I would use
(https://mobileimages.lowes.com/product/converted/027426/027426134072.jpg) 

Wood conditioner before using stain to prevent blotchy stain (pine will get very crappy looking if you do not condition the wood)
Then stain
Then Poly..

Put on lots of coats of poly to fill the grain.  Once you have some buildup - sand between coats with 220G to knock off the lumps and bumps. 
You can fill the scratch with poly and build it up..

You can also try a damp cloth and a iron (like you are ironing a shirt) over the scratch to see if you can swell it back to shape..  This works if the wood fibers are not cut/torn..
good luck.